A panel of 15 candidate targets will be identifed based on both high-frequency amplified chromosomal regions and mRNA overexpression from a SNP array database of specimens of neoplastic Barrett's esophageal mucosa with support from Core B. Validafion of selected gene candidates will be performed on an independent set of 50 cases of Barrett's metaplasia, low-grade, high-grade dysplasia and adenocarcinoma using quantitative RT-PCR and at the protein level using fissue microarrays and immunohistochemistry with support from Core C. This panel will be reduced to the 5 best candidate amplified and/or overexpressed cell surface genes will be transfected into immortalized Barrett's metaplasia cells for in vitro selection of imaging peptides in Project 2 for imaging with a mulfi-spectral scanning flber endoscope developed in Project 3.